1. Field of the Invention
The present invention relates to a novel aqueous lubricating composition and the process of manufacturing same.
2. Description of the Prior Art
A water-based lubricant is of particular interest to the engineering industry which has need of an economical fluid which does not employ a traditional hydrocarbon-based lubricant and which performs better than the existing water-based lubricants. Examples of these are a non-flammable fluid for use in mines, a fluid for improving the reliability of metal-forming operations and increasing the rate of such operations, a fluid with a high degree of heat conduction in the order to make new mechanical concepts possible, and economical fluid for the lubricating tools in boring and other operations.
Numerous compositions have already been proposed for such purposes, as for example soap solutions and oil-water emulsions possibly mixed with a fatty acid.
The present invention relates more particularly to lubrication employing metallic salts of fatty acids or metallic carboxylates. Alkali metals or alkaline earth metal stearates have been investigated previously.
Two principal difficulties and limitations have been encountered in using these products, namely
(1) The lubricating power of these products is relatively mediocre and is incompatible with severe industrial uses. It is necessary to use in addition to the aforesaid metallic soaps, additives for use under extreme pressure PA1 (2) The majority of metallic carboxylates are substantially insoluble in water. The only exception to this rule are certain alkali metal carboxylates, notably those of sodium, but their lubricating power is, however, mediocre. It is thus necessary to use metallic carboxylates suspended in water. This requires the use of dispersing agents. Moreover, it is well known that the suspensions obtained are relatively unstable and that they precipitate in from several minutes to several hours. It thus becomes necessary to use stabilizing agents.
It has been proposed to use compositions including one or more alkali metal carboxylates; one or more surface active agents and a dispersing agent; certain organic compositions as stabilizing agents; and certain sulphur or chlorine agents as extreme pressure agents for example, French Patent Specification No. 2158265 (Parker) discloses an aqueous suspension of stearates of calcium, magnesium, aluminum and barium, as dispersents anionic, cationic non-ionic surface active agents, a composition acting as a stabilizer, and chlorinated paraffin, and/or sulphonated fatty oil as extreme pressure additives.
In the prior art there is no aqueous-based lubricant strictly free of oil which is both stable and effective